Looked up two definitions of rescue. First, is the default that shows on Google (via Oxford Languages) [1]:
> verb. 1. save (someone) from a dangerous or distressing situation. 2. informal, keep from being lost or abandoned; retrieve.
Per this one, if you miss the last train across the bay the the Uber _would_ indeed be "rescuing" you if you felt distressed. If we consider the informal definition, I'd say you're also being rescued since one could say you were abandoned by the train and thus being retrieved by the Uber. Next, Merriam Webster [2]:
> transitive verb. to free from confinement, danger, or evil
Similarly, if you understand "rescue" as freeing someone from danger, this isn't a rescue. The astronauts aren't in danger really— they have all the supplies and support they need. Nonetheless, they certainly are in confinement, so this could still be called a rescue.
I personally do see how the fact this mission was already scheduled, and the little danger around all this, can make "rescue" feel like a little much. It's the same word used in The Martian, after all. But nonetheless I would still call it a rescue mission. These two astronauts are confined up there not by will but by circumstance, and the taxi flight was modified to sending only two people instead of the usual four, specifically to make space for these two astronauts to come back [3].
[1] https://www.google.com/search?q=rescue%20meaning
[2] https://www.merriam-webster.com/dictionary/rescue
[3] https://apnews.com/article/boeing-spacex-nasa-astronauts-sta...